Issue _doing_it_wrong() when invalid path is provided to registered style

Author: westonruter

src/wp-includes/script-loader.php

@@ -3081,7 +3081,18 @@ function wp_maybe_inline_styles() {
 		$path = $wp_styles->get_data( $handle, 'path' );
 		if ( $path && $src ) {
 			$size = wp_filesize( $path );
-			if ( ! $size ) {
+			if ( 0 === $size ) {
+				_doing_it_wrong(
+					__FUNCTION__,
+					sprintf(
+						/* translators: 1: 'path', 2: filesystem path, 3: style handle */
+						__( 'Unable to read the "%1$s" key with value "%2$s" for stylesheet "%3$s".' ),
+						'path',
+						esc_html( $path ),
+						esc_html( $handle )
+					),
+					'7.0.0'
+				);
 				continue;
 			}
 			$styles[] = array(
@@ -3120,6 +3131,20 @@ static function ( $a, $b ) {
 
 			// Get the styles if we don't already have them.
 			$style['css'] = file_get_contents( $style['path'] );
+			if ( false === $style['css'] ) {
+				_doing_it_wrong(
+					__FUNCTION__,
+					sprintf(
+						/* translators: 1: 'path', 2: filesystem path, 3: style handle */
+						__( 'Unable to read the "%1$s" key with value "%2$s" for stylesheet "%3$s".' ),
+						'path',
+						esc_html( $style['path'] ),
+						esc_html( $style['handle'] )
+					),
+					'7.0.0'
+				);
+				continue;
+			}
 
 			/*
 			 * Check if the style contains relative URLs that need to be modified.

tests/phpunit/tests/dependencies/styles.php

@@ -768,6 +768,25 @@ public function test_wp_maybe_inline_styles_no_path() {
 		$this->assertSame( $GLOBALS['wp_styles']->registered['test-handle']->src, $url );
 	}
 
+	/**
+	 * @ticket 64447
+	 *
+	 * @covers ::wp_maybe_inline_styles
+	 * @expectedIncorrectUsage wp_maybe_inline_styles
+	 */
+	public function test_wp_maybe_inline_styles_bad_path() {
+		$handle   = 'test-handle';
+		$inc_path = '/css/ancient-themes.css'; // Does not exist.
+		$url      = '/' . WPINC . $inc_path;
+		wp_register_style( $handle, $url );
+		wp_style_add_data( $handle, 'path', ABSPATH . WPINC . $inc_path );
+		wp_enqueue_style( $handle );
+
+		wp_maybe_inline_styles();
+
+		$this->assertSame( $GLOBALS['wp_styles']->registered[ $handle ]->src, $url );
+	}
+
 	/**
 	 * @ticket 63887
 	 */